The pressure to feed results into a controversial, expansive DNA database has bogged down the FBI's DNA lab so badly that there is now a two-year-and-growing backlog for forensic DNA testing needed to solve violent crimes and missing persons cases.

Civil libertarians call the database — which increasingly includes everyone convicted of every federal law, legally innocent people awaiting trial and non-citizens detained in the U.S. for any reason — unnecessary and unconstitutional.

And yet a review by the Department of Justice's Inspector General released on Monday concludes that the need to analyze and upload some 96,973 or more DNA samples a year into that database is contributing to a backlog of forensic DNA cases that stood at 3,211 in March.

That translates into a delay of about 150 days to over 600 days for law enforcement agencies who need answers right away.